This invention generally relates to a stent, and more particularly, to a device for insertion in the lumen of hollow organs and tubular parts of the bodies of animals, including humans, for supporting and holding open the organs or body parts such as blood vessels, trachea, ureter, esophagus, viscera or any tubular or hollow organs during treatment of diseases. The stent includes a longitudinal passageway for conveying fluids and solids through the lumen of body parts.
Stents have been known and used in the past. Although the diameter of conventional stents is expandable in order to be fixed in place and to maintain dialation, they cannot be removed. The problem with conventional stents is that they can be changed in diameter to fit a particular hollow organ or body part and anchored in place, but once this is done, they cannot be reduced in size and removed.
Some conventional stents are helixes or springs that can be compressed parietally of transversely and may change in diameter. Solids can possibly become lodged between the coils of the stent. This will block the flow of fluids through the organ or tubular body part. Also, the body can build up fibrous tissues, neointima, fiberous tissue or plaque around or inside the coils of the stent. When this happens, the stent becomes embedded in the body tissues and is difficult or impossible to remove.
In conventional stents designed with rough surfaces (gaps and holes such as netting or helixes), the body can build up fibrous tissue or neointima on the rough surface, obstruct or occlude the movement of solids or fluids through the body part thus preventing extraction of the stent. Secondarily, solids passing through the body part could become embedded in the rough surface of the stent and obstruct movement of material through the body part. Conventional stents, therefore, usually are not removed, but become permanently implanted.